This invention relates to an electric distribution box such as a relay box, a fuse box or an electric control unit box which is mounted in a vehicle such as a automobile and incorporates an electric component such as a relay, a fuse or an electric control unit, and more particularly to an electric distribution box having an exterior cover of resin for incorporating the interior component and a molding hole (shape-punching hole) from which water may externally invade formed on the bottom wall of the exterior cover.
For convenience of molding, resin molded products may generate a molding hole for removing a metallic mold (e.g. see Patent Reference 1).
Where such a molding hole exists on the exterior cover of the electric distribution box requiring waterproof capability, rain water may invade from the molding hole. So, usually, the molding hole is covered with a cap. However, the cap itself may have a small molding hole for forming a locking piece. In such a case, in order to prevent water from invading from the molding hole, this molding hole is arranged on a flange being in intimate contact with the wall of the cover. However, it has been found that because of a clearance necessary in locking, a gap may be generated between the flange and the cover, and water may invade through the gap.